The present invention relates to drug targeting by small emulsion droplets, using biologically active targeting molecules. The advantages of being able to direct the drug to the tissue or cells where it is required, and to minimize the amount delivered to inappropriate sites has implications for many clinical situations, such as cancer chemotherapy, inflammations and viral infections (Davis S. S et al. Drug Exptl. Clin. Res. 9, 632, 1985).
In the past, several attempts to achieve drug targeting were reported, by using polyclonal and monoclonal antibodies. These attempts include:
1. Direct chemical attachment of drug molecules to an antibody molecule. PA1 2. Chemical attachment of drugs to antibodies through the use of a linkage polymer molecule such as dextran. PA1 3. Attachment of small antibodies to small biodegradable polymeric particles, by covalent linkage by direct adsorption or by adsorption via protein A. PA1 4. Coupling of liposomes with monoclonal antibodies via hydrophobic modification of the antibody. PA1 a) Covalent attachment of drug molecules require development of a chemical binding process for each drug to be tested. PA1 b) Direct attachment to the antibody may reduce its biological activity. PA1 c) only a limited amount of drug molecules may be bound. PA1 d) The clinical effects of the drugs may be altered upon chemical attachment. PA1 e) Possible leakage of drugs if liposomes are used. PA1 f) Desorption of the antibodies may occur if it is physically adsorbed to a solid particle. PA1 a) dissolving the desired drug in an oil phase; PA1 b) formation of an oil/water emulsion; PA1 c) formation of a surface-active-antibody by chemical attachment of various hydrophobic groups to the antibodies; PA1 d) mixing the surface-active antibody with the emulsion.
The above suggested method to achieve drug targeting have many disadvantages:
The present invention will provide a novel drug targeting method, which would overcome most of the above disadvantages, by the use of emulsions and micro emulsions.